The Universal Description Discovery and Integration (UDDI) standards project aims at speeding up interoperability and adoption of Web services by enabling enterprises to quickly and dynamically publish, discover and invoke such services. UDDI advances this goal through the creation of standards-based specifications for service description and discovery. The UDDI standard provides for registries to be set up on the internet that allow providers of web services to publish information about these services on a certain registry and allow users of web services to search that registry for web services they want to use. The current version of UDDI is UDDI v3.
UDDI v3 registries store several persistent data structures called entities or artifacts. Artifacts are stored in eXtensible Markup Language (XML) format. UDDI v3 artifacts include the following types: Business Entity, Business Service, Binding Template, tModel, Publisher assertion, and Subscription. A Business Entity describes a business or other organization that provides web services. A Business Service artifact is linked subordinately to a Business Entity and describes a collection of related web services offered by the business described in the Business Entity. A Binding Template is linked subordinately to a Business Service and describes the technical information necessary to use a particular web service. A tModel is a reusable model of a concept that may be referenced by other artifacts, usually Binding Templates. Concepts that a tModel can model include a type of web service or a taxonomy system or a protocol used by web services. A Publisher Assertion is linked subordinately to a Business Entity and describes the relationship that Business Entity has with another Business Entity. A Subscription describes a standing request to keep track of changes to the artifacts described by the Subscription.
There are several types of entities that interact with a UDDI v3 registry. An Operator is a person or organization that maintains an instance of UDDI v3 registry software and typically hosts the server that the UDDI v3 registry software instance runs on. A software instance that interacts with a UDDI v3 registry and is a Client. A person or organization that the client acts on behalf of is a User. A Publisher is a user that establishes or changes artifacts on a UDDI v3 registry. Other users may access the registry to find a web service to use.
The UDDI v3 standard provides a variety of mechanisms to classify a web-service artifact in terms of standard and custom classification criteria that are objective. These classifications can only be established or altered by the owning publisher of the UDDI v3 artifact. However, the UDDI v3 standard does not provide a means for the users of a UDDI v3 registry to publish their own, subjective evaluations about the perceived “quality” of a web-service or other artifact found in the UDDI v3 registry, and to search for a web-service based on such subjective criteria. Nor do the currently known providers of UDDI v3 registers (e.g. registries from Systinet, Microsoft, SAP, Apache, Oracle) provide a means for a user of the UDDI v3 registry to publish a subjective evaluation of an artifact from this registry and later to search for artifacts on the basis of such subjective evaluations.